Honing machine



Sept. 26, 1,939., H, BLOQD ETAL 2,1749

HONING MACHINE Filed oct.. 2, 1956 7 sheets-sheet 1 Sept. 26, 1939. H. L. BLOOD E'rAL 2,174,029

HONING MACHINE Filed oct. 2A, 193e vsheets-sheet V2 234 e I A 3mm/ums lfro @50037 J- j y wccwn .adC/amaa- Sept 26, 1939 H. 1 BLOOD Er AL 2,174,029

HONING MACHINE Filed A(mf-2, 1936 7 sheets-*sheet s Sept 25, 1939. H. l..v BLOOD ET Al.` 1 2,174,029

HONING MACHINE 'u Filed Ot. 2, 1956 7 Sheets-Sheet V JJ. l@ J2 J32) x Jal 3 24 23 l 152 mi? @2l Q20 WE J5 .720 Jl v J8 f 151 ,9 J44 o 4s 14a o i e r/ T122 J2 6 Jas J@ 147/ ze J J7 Jaz Sept.' 26, 1939. H. I BLOOD Er Al. 2,174,029

HON ING MACHINE Filed Oct. 2, 1956 y 7 Sheets-Sheet 6 74N N 64 @JL SePt- 26, 1939. H. l.. BLOOD ET AL 2,174,029

` HONING MACHINE Filed Oct. 2, 1936 '7 Sheets-Sheet 7 Patented Sept. 26, 1939 Fries.

2,174,029 Home Maa Harold i.. Blood and William n. schmidt,

Worcester, Mass., assignors to The Heald Machine Company, Worcester, Mass., a corporation oi' Massachusetts Application October 2, 1936, Serial No. 103,725

s claims.

The present invention relates to a machine adapted for the honing of Workpieces and is especially intended for the successive honing of a plurality of uniformly sized Workpieces.

In prior devices for honing, either the workpiece or the hone has been rotated at a pre` determined rate throughout the entire honing operation and, although a suitable finish is obtained, a greater length of time is required than against the workpiece the desired surface iinish SEE will be obtained in a predetermined time interval and the present invention also provides for bringing the honing operation to a` close after the honing members have been operating upon the workpiece for a predetermined time.

The honing members are generally in the form of small stones of abrasive material and, as the stones are used, they gradually become worn, making necessary an adjustment of the position of the honing members to compensate for the wear thereon. The present invention incorporates a structure for automatically compensating for Wear on the hones so that the compensation takes place when necessary independently of the individual honing operations. By this compensation, the honing stones always exert the required pressure on the Work for obtaining the desired surface iinish; y

As the stones become more and moreworn the holdersl on which the stones are vmounted appreach and ultimately engage the surface of the workpiece. if the honing operation continues after this occurs the surface ofthe workpiece will be scratched or damaged lby the holder, thus making the workpiece unsalable.. The present invention incorporates a mechanism by, which the entire machine is brought to rest after any one of the honing members becomes worn to such an extent as to be no longer usable. This mechanism is arranged to prevent the further operation of the machine, afterhaving been brought to rest, until the worn honing member, or members, have been replaced by unworn members l which will produce a satisfactory honing operation on the workpiece.

. Other and further objects and advantages of e the invention will more fully appear from the 5 following detailed description taken in. connection with the accompanying drawings in which- Fig. 1 is a front elevation of a machine embodying the invention, with parts broken away to show certain features. l0

Fig. 2 is a plan View of the machine, also with parts broken away.

Fig. 3 is a vertical sectional view substantially on the line 3 3 of Fig. 1.

Fig. i is a horizontal sectional view through 15 the machine substantially along the line 4-4 lof y Fig. 1.

Fig. 5 is a fragmentary vertical sectional view substantially along the line 5 5 of Fig. 3.

- Fig. 6 is a view in elevation, with parts broken 20 away, of the two-speed drive mechanism `for the honing members.

Fig. 7 is a sectional view along the line 'l--l of Fig. 6.

Fig. 8 is an elevation of the mechanism within 25 the control box on the front of the machine.

Fig. 9 is a iiuid pressure diagram.

Fig. -10 is a wiring diagram.

Fig. 11 is avertical sectional view on a larger scale, through one of the hones. 30

Fig. 12 is an elevation, with parts in section, ofl

one of the honing heads, together with the mechanism which compensates for wear on the honing stones.

Fig. 13 is an end view of two of the honing 35 heads as seen from the left in Fig. 12. 5

Fig. 14 is a fragmentary elevation of one of the honing stones and its supporting mechanism showing the position of the parts when the hones have been materially worn. o

Like reference characters refer to like parts in the different gures.

With reference first to Fig. 1, the machine, which discloses one embodiment of the invention, has a base I on which is mounted for reciproca- 45 tion a table 2, the base being provided with guide- Ways 3, Fig. 3, on which the table is slidable. A bridge i, Figs. 1 and 3,.spans the guideways and extends over the table at one end of the base.

Either the work or the hone may be mounted on 50l Aus honing heads are mounted in a. bracket 5 secured to the table.

This bracket incorporates an automatic loading mechanism which is not a part of the present invention. It is sufllcient to note that the workpiece a to be honed is positioned in a cylindrical bore 1 in the bracket 6 and is in'axial alinement with the hone 8 on each honing head 5 for engagement'by the hone as the table movesto the left to bring the hones and workpieces into engagement. charged and unhoned workpieces automatically placed in operative position by a suitable mechanism preferably controlled by the table movements. Thus, as the table moves to the left into operative position, an unhoned workpiece `is positioned in alinement with each hone and in proper position in the workholder.

The table 2 is shifted by' any suitable mechanism, as'by the uid pressure actuated mechanism, best shown in Fig. 5. With reference to this figure, the base I has positioned therein a cylinder 9 in which is located a piston I0, the projecting piston rod II of which is connected to a lug I2 projecting downwardly from the tab1e.

Fluid under pressure is directed alternately to opposite ends of the table cylinder by means of 'a reversing valve I3, Fig. 9, located in a casing -I4, which, as shown in Fig. 8, is positioned in a control box I5 on the front of the base. The position of the main reversing valve I3 is under the control of a pilot valve I6, Figs. 8 and 9, in a casing I1, also located within the control box.

A reversing lever I8 pivoted on a stud I9 on the base has one end in engagement with the projecting stem of the pilot valve and the opposite end is in a position for engagement with spaced reversing dogs 20 and 2I which Vare adjustably mounted on the front of the table and which provide for 'a reciprocation of the table in operative position. The reversing dog 2I is pivotally mounted on a pin 22 carried by a block 23 to provide for raisingl of said dog (to the position of Fig. 8) to render it inoperative, thereby allowing an extended movement of the table to the right (Fig. 1), for withdrawing the workpieces from operativeposition. An additional reversing dog 24, also adjustably mounted on the table, is in a position ior engagement with the reversing lever as the table reaches the end of its movement into workpieces being inserted in the workholder during the extended movement. The uid pressure mechanism will be described in detail later.

Referring again to Fig. 8, the movements of the table into and out of operative position occur preferably at a maximum rate of table travel and the reciprocations of the table in operative position occur at a relatively slow rate as determined by a throttle valve 25 in a casing 26 within the `control box I5. The projecting end of the valve 25 is in a position for engagement with an arm 21 mounted on a stub shaft 28 journalled in the base of the machine. An arm 29 is also mounted on the shaft 28 for turning movement therewith. The free end of the arm 29 extends upwardly into engagement with the under surface of a block 30 adjustably mounted on' the table', and this block, when the table is in operative position, engages and depresses the arm 29, turningV the arm 21 down and thereby shifting the throttle valve to The honed workpieces are dis- Each honing head 5 comprises a housing 3I, Fig. 12, secured to the upper side of the bridge and within each housing is suitably journalled a spindle 32 having secured to its left hand end a pulley 33 by which the spindle is rotated. One hone 8 is mounted on the right hand end of each spindle in a position to engage a workpiece in the work-supporting structure. -The pulleys 33 for the several honing heads are connected by belts 34, Fig. 1, to the driving pulley 35 of a two-speed drive mechanism 36, Fig. 4. Suitable idler pulleys 31, Figs. 1 and 13, take up the slack in the belts and are positioned to provide a suitable wrap of the belts around each of the pulleys.

A driving motor 38, Fig. 4, has a driving connection with the two-speed drive mechanism 36 and this connection in the arrangement disclosed embodies a sprocket 39 on the motor shaft 40 connected by a chain belt 4I to a sprocket 42 on the driven shaft 43, (see also Fig. 6) of the mechanism for a positive rotation of the driven shaft 43 at all times.

With reference to Fig. 6, the driven shaft 43 is journalled in the housing 44 of the two-speed drive mechanism, and has secured thereon a gear 45 which is in mesh with a gear 46 on a'countershaft 41, also journalled in the housing 44. The countershaft has a-second gear 4B which is in mesh with a gear 49 connected by means of a one-direction clutch, shown in Fig. .'7, to the driving shaft 50 of the mechanism, the latter having secured to its outer end the pulley 35. A disk clutch 5I provides a direct connection between the shafts 43 and 50, which are in alinement with each other, and this clutch is rendered operative by axial movement of a hub 52 which is axially slidable on the shaft 50, but held against' turning movement thereon by 'a key 53, Fig. 7. The hub 52 lhas a plurality of notches 54 therein, in each of which is positioned a roller 55,\and the gear 49, in the form of a ring, is journalled on the periphery of the hub 52. As shown in Fig. '7, the notches 54 are of such a shape that the gear 49 is free to turn counterclockwise on the hub, but cannot turn clockwise without a corresponding movement of said hub. 1

The hub 52 also has a radial flange which forms a piston 56, Fig. 6, slidable in a cylinder 51 provided by the housing 44, and the axial shifting movement of the hub for rendering the clutch 5I l operative is procured by directing fluid under pressure to the cylinder 51 at the`leit hand side of the piston 56,

When fluid under pressure is directed to the cylinder 51 the, clutch 5I is operative and the pulley 35 is driven directly from the shaft 43 and at the same rate of speed, with the gear 49 turning freely on the hub 52. When the rate of rotation of the hones is to be reduced, the fluid in the cylinder 51 is allowed to exhaust by means of a valve 58, Fig, 9, hereinafter described. 'I'he clutch 5I then becomes inoperative so that the drive for the hones is through the countershaft 41, at which time the gear 49 is directly connected to the hub 52 by means of the rollers 55, and procures a rotation of the pulley 35 at a relativelyv slow rate of speed, as determined by the relative sizes of the gears 45, 46, 48 and 49.

The hone disclosed is similar to the hone described in a copending application illed by Blood, one of thepresent applicants, Serial No. 100,580, led September 14, 1936, although any other similar type of hone can be used. It is suillcient to note for the purposes of the present application that the hone comprises a head or arbor 1 key 62 engaging with a keyway 63 in the spindle to hold the latter against rotation. The head 59 also has a plurality of radial slots 6I, in each of which is positioned .a hone carrying lever 85. The spindle 6| has an arcuate shoulder 66 engageable with an arcuate protuberance 61 ,at the corner of each of the levers. Thevspindle 5|, as shown, is made up of separate elements which are, however, functionally integral andare so described. A cylindrical hub 68 on the head has an internal thread to provide for attachment to the end of the spindle 32 in the honing head.

Surrounding the head at the base of the slots is a ring 69 secured to the head, as by bolts 10, one of the latter holding the key 62 in position. Between the ring 69 and the head is clamped a resilient annular disk 1| in the form of a diaphragm having fingers 12 projecting inwardly into the several slots 64.

Each lever 85 has an arcuate lug 13 at one end for engagement with the inner or left hand side of the corresponding flnger12 to -permit rocking movement of said lever about the lug. The opposite end of the lever has an arcuate lug 14 which engages in an arcuate recess 15 in a hone carrier 16. On the outer side of each carrier is a plate 11 to which is secured, as by suitable adhesive, a honing member in the form of a stone 18, generally of abrasive material. The honirig stones are additionally held on the carrier plates A,'li by ilanges 19 extending outwardly from the plates.

The plates 11 are releasably held on the carriers by coil springs and 8|, each in the form of an annulus. The spring 80, is positioned at the inner or left hand end of the plates and engages with the anges 19 on the plate. The other coil spring 8| is positioned in a recess 82 in the-outer end of each of the plates, the inturned portion of the plate which forms the recess engaging in a correspondingly shaped recess 83 in the carrier. Not only do these coil springs hold the plates on the carrier, but they also hold the carriers in engagement with the corresponding levers 05and hold the levers 65 against the spindle 8|. The levers are also held in predetermined relation to each other by a coil spring 80 also in the form of an annulus, and positioned in a slot 85 provided in the head 50. The spindle 6| has an axially positioned bolt 80 in the end thereof by which to control the effective length of said spindle, the boltbeing locked in adjusted position by a clamping nut 8l. Y

For expanding and contracting the hone, the spindle 32 has an axial bore 88, Figs 1l and 12, in which the inner end of thel spindle 6| is received. Within the spindle bore 38 is located an actuating rod 89, having at the right hand end thereof a plunger @I0 engageable with the head of the bolt 80, and the rod is resiliently urged tothe right by a compression spring 9| surrounding the rod and positioned between the plunger and a collar 92 positioned within the bore 88. Movement of@ the rod 89 to the right, Fig. 12, for expanding the hone is limited by a nut 93 engaging with the threaded left hand end oi' the rod, said nut having a projecting fiange 94- engageable with the end of the pulley 33. A second nut 95 on the rod is held against turning movement relative to thenut 93 by a pin 96 extending through both nuts, and a coil spring 91, positioned in opposed recesses 98 and 99 in the nuts 93v and 95, respectively, urges the nuts apart to place a i'rictional drag thereon so that the nuts are irictionally held against turning movement.

When the honing stones become worn the nuts 93 and 95 are backed away on the'rod to compensate for the reduction in size of the stones,

and this backing away is automatically effected by the mechanism of Figures 12 and 13. With reference to these ilgures, the nut 93 has a collar |00 extending therearound and in a position for engagement with a radial ilange |0| on the nut 95. The collar is mounted in an open slot |02 in an arm |03 and is carried by bolts |00V extending inwardly -from opposite sides of said slot and providing trunnions for said collar. The arm |03 is journalled on a pin |05 in a bracket |06 secured to the honinghead. A projecting bar |01 forming part of the arm |03 has an adjustable stop |08 engageable with a part of the bracket |00, and an adjustable stop |09 in the bracket is engageable with the bar |01, the cooperating stops |08 and |09 limiting the rocking movement of the arm |03 in both directions.

The lower end of the arm |03 has a plunger ||0 slidably mounted therein and normally urged into the right hand position of Fig. 12 by a coil spring surrounding the plunger. The movement of the latter to the right is limited by adjustingI nuts ||2 on said plunger. The plunger is in a position for engagement with the end of the table 2 as the latter reaches operative position, and an oscillation of the arm* |03, as controlled by the stops |08 and |09, occurs during the reciprocatory movement of the table during the honing operation.

In the normal oscillatory movement of the arm |03, the collar |00 does not come in contact with the flange on the nut 95, since the latter is also moved to the leftas the result of the table movement to the left when the workpiece is in operative position, the rec-iprocations of the workpiece providing a corresponding reciprocation of the rod 89. As the hones become worn so that compensation for wear is necessary, the nut 95 gradually comes into contact with the collar |00 with suillcient pressure for the nut to be held against turning movement until the nuts 83 and 95 have been backed oi a slight amount on the rod 89. Obviously, the spindle 32 in which the rod 89 is positioned must be rotated in the direction indicated by the arrow H3, Fig. 12, so that the nuts 93 and 95 will be turned in the proper direction.

The machine is arranged to provide for a honing operation at two separate speeds, with the hone rotated relative to the workpiece at one speed for a predetermined interval and subsequently rotated at a diierent speed as determined by the two-speed drive for another predetermined interval,l at the end of which time the honing operation is brought to a close. To this end, the operation is under the control of two separate timerslM and H5, Fig. 9, of any suitable character. .Timers of this character are well known and it is suilicient to note for the purpose of the present invention that each timer is intended to operate a predetermined time after having been set in operation, with the time interval preferably adjustable as desired.' In the arrangement shown, the timers are both set in operation together, and the timer H4 operates after the lapse of a few seconds and procures the change in the rate of rotation-of the hone, or any other change in the honing operation, and the second timer ||5 operates a predetermined time w thereafter to render the reversing dog 2| inoperative for a runout of the table, bringing the honing operation to a close.

When the timer ||4 operates, it energizes a solenoid ||6, Fig. 9, through a circuit hereinafter described, to shift the valve 58 located in a casing ||1 for directing fluid under pressure to the cylinder 51, thereby changing the rate of rotation of the hones. When the timer I I5 operates, it energizes a solenoid I|8 which is connected to a lever ||9 -journalled on a stud |20 in the base of the machine. The upper end of this lever is moved into alinement with the reversing dog 2|, when the solenoid H8 is energized, and elevates the latter so that it is carried over the end of the reversing lever I8 without engagement therewith, allowing the table. to move to the right into the position of Fig. 1.v

With reference again to Fig. 9, the fluid pressure supply for the machine `is provided by a pump I 2| which, as shown in Fig. 4, is directly connected to the driving motor 38 and is accordingly operated whenever the driving motor is rotating. Fluid under pressure from the pump is directed by a conduit |22 to a port |23 in the casing 26 for the slow-down valve 25. 'Ihe valve has a reduced portion |24 which normally provides a uid connection between the port |23 and a second spaced port |25 which is connected by a conduit |26 to the inletport |21 in the reversing valve casing I4. `A throttle valve |28v is positioned in the port |21 and determines the maximum rate of travel of the table. Spaced ports |29 and |30 in the reversing valve casing I4 are connected to the left and right hand ends of the table cylinder 9 by conduits |3I and |32 respectively. The valve casing Ill also has spaced exhaust ports |33 and |34. The valve |3 has spaced reduced portions |35 and |36 which normally provide a iiuid connection between the inlet port |21 and one of the outlet ports |29 or |30, the other outlet port being simultaneously connected to one of the exhaust ports |33 or |34.

The position of the reversing valve I3 is under the control of the pilot valve I6, and the conduit |22 has a branch conduit |31 connected to a port |38in the casing I1 for the pilot valve.

Spaced outlet ports |39 and |40 in the casing I6 are connected by conduits |4| and |42 to the opposite ends of the reversing valve casing I4. The casing |1 has spaced exhaust ports |43 and |44. The pilot valve I6 has spaced reduced portions and |46 which provide fluid connection between the port |38 and either of the ports |39 or |40 selectively, the other of the latter ports being simultaneously connected to either of the exhaust ports |43 or |44. The position of the.

pilot valve thereby controls the position of the reversing valve by the alternate admission of fluid under pressure to opposite ends of said reversing valve so that the movements of the table are controlled by the movements of the reversing lever I8.

The slow-down valve. 25 becomes operative by downward movement thereof when the table reaches operative position for procuring a slow reciprocation of the table. Referring again to Fig. 9, the casing '26 for the slow-down valve has a channel |41 in which is positioned a throttle valve I 48. The opposite ends of the channel |41 are in alinement' with the ports |23 `\and |25, respectively, and when the valve 25 is shifted downwardly bythe dog 30, the fullsized portion |49 of said valve cuts off the direct connection between the ports' |23 and |25 and -casing also has an exhaust port |61.

i iluid under pressure for actuating the table must accordingly pass through the channel |41 so that the table movements are under the control of the throttle valve |48.

When the slow-down valve 25 is shifted downwardly as the table reaches operative position, iluid under pressure is directed around -a reduced portion |50 of the valve 26 from an annular groove |5| connecting with the port |25, to a port |52 in the casing 26. The port |52 is connected by a conduit |53 to the end of a cylinder I 54 in which a plunger |55 is slidable. .Fluid ,under pressure thus enters the cylinder |54 at the beginning of the honing operation to set the timers in operation.

As the valve 25 is released at the end of the honing operation and moves upwardly to the position of Fig. 9, the reduced portion |50 of the valve establishes fluid connection between the port |52 and an exhaust port |56'to allow the plunger |55 to move downwardly under the action of a spring |51 in readiness for the subsequent honing operation,

As shown in Fig. 9, the plunger |55 has a crossbar |58 attached thereto, in which are positioned two slidable rods |59 and |60, urged upwardly by coil springs |6| and |62, connected at their lower ends to the timers I I4 and |5 respectively. The upward movement of the plunger |55 carries with it the rods |59 and |60 and thus sets the timers in operation.

After the honing operation is started the honing continues until the timer ||4 operates to change the rate of rotation of the hone relation .to the workpiece. Referring again to Fig. 9, the fluid pressure outlet |22 from the pump is connected by a conduit |63 to a port |64 in the casing I|1. An outlet port |65 in the casing I|1 is connected by a conduit |66 to the cylinder 51, and the A reduced portion |68 of the valve 58 normally provides a connection between the ports |65 and |61 so that the piston 5s is allowed to remain at the' left hand end of the cylinder 44 in order that the hone may operate at a high rate of speed. When the timer ||4 becomes operative to energize the solenoid H6, the reduced portion |68 provides fluid .connection between'the ports |64.and |65, thereby procuring movement of the piston 56 to the right for reducing the rate of rotation of the hone.

The electrical connections for the machine are best shown in Fig. 10. With reference to this figure, the motor 38 for the machine is connected through a motor control switch |69 of conventional construction to the sourceof power 10 which may be a three wire system. A switch |1| is normally closed and the rotation of the motor is under the control of the motor control switch |69 which is manually controlled by starting and stopping switch |12 and |13 in a box I 14 pos!! tioned on the front of the machine. The three supply leads |15, |16'and |11 from the power supply |10 are connected to contacts |18, |19 and of the control switch |69, and, when the control switch is closed, the movable element .I 8| thereof has connectors |82, |83 and |84 which provide a connection respectively between the contacts |18, |18 and |80 and corresponding con-V tacts |85, |86 and |81 connected by leads |88, |89 and |90 to the motor 38. l

'I'he movable element 8| is shifted by a solenoid |9I, one terminal of which is connected by a lead |92 to the contact |19 of the control switch. The solenoid |9| is energized when the normally -to one contact 203 of a solenoid-operated switch 204 which is held in closed position by a spring 205. A lead 206 connects the second contact 201 of the switch 204 to the primary winding 208 of a transformer 209, this winding being also connected by a lead 2|0 to the solenoid |9|. Thus, when the starting switch |12 is closed the solenoi d |9| is energized to close the control switch |69 for starting the machine.

The terminal |91 of the starting switch is also connected by alead 2|| to one contact 2 |2 of the stopping switch |13, which, as shown, is normally closed. The other contact 2|3 of this switch is connected by a lead 2|4 to a contact 2|5 of the switch |69. When the control switch |69 is closed the circuit through the solenoid |9| is closed by a connector 2|6 which connects the contacts |95 and 2|5 and is similar to the connectors |82 and |83, and the switch |69 is thus held closed. However, when the stopping switch |13 is opened, the solenoid is deenergized and the control switch |69 is allowed to open.

Again referring to the electrical diagram of Fig, l0, one terminal of the solenoid ||8 is connected by a lead 2|1 to the lead |15 and the other terminal of this solenoid is connected by a lead 2|8 to one contact 2|9 of the time-controlled switch 4. The other contact 220 of this switch is connected by a lead 22| to the main supply lead |16. The solenoid ||6 is accordingly energized when the time switch ||4 operates .to provide a connection between the contacts 2|9 and 220, thereby shifting the valve 58 for changing the rate of rotation of the honing head.

The solenoid ||8 has one terminal connected by a lead 222 to the lead 251 and thence to the supply lead 223 to one contact 224 of the timecontrolled switch H5. The other contact 225 of this time switch is connected by a lead 226 to the lead 22| and thence to the supply lead |16. The solenoid ||8 is accordingly energized when the time-controlled switch I5 operates for terminating the honing operation.

` winding 229 of the transformer 209. The other the solenoid 23| thereby breaking the electrical connection between the two contacts 203 and 201 of this switch, deenergizing the solenoid |9| and bringing the machine immediately to rest.

In the operation of the machine when an unhoned workpiece has been properly positioned' within the work-suporting structure, movement of the tableto the left to bring the work and 'hones into operative relation. is procured by `shifting of the pilot valve I6, as by meansof the handle 234, Fig. 1, positioned on the front of the base. As the work moves into operative position,

lthe valve 25 is shifted by the cam 30 for setting thetimers ||4 and ||5 in operation, so that both the solenoids I6 and ||8 are de-energized. When the solenoid ||6 is deenergized the valve 58 is shifted to the position of Fig. 9 to allow the piston 56 to move to 'the left forprocuring a slow rotation of the hone within the workpiece. Deenergization of the solenoid |8 allows the reversing dog 2| to move into operative position for controlling the reciprocations of the table during the honing operation.

After the honing operationhas continued for a predetermined time the timer |'|4 becomes operative, thus energizing the solenoid ||6 for shifting the valve 58 to the right, thereby increasing the rate of rotation of the hone within the workpiece.

The honing operation continues at this fast rate until the timer ||5 becomes operative, thus energizing the solenoid |36 for elevating the reversing dog 2|, thereby procuring a run-out of 'the table to the position of Fig. l. During the runout of the table the honed workpiece or workpieces are discharged from the workholder and an unhoned workpiece is-placed in operative position in the work-support. The dog 24 then engages and rocks the reversing lever [8 for returning the table to the left to bring the unhoned work-piece into operative relation to the hone.

The honing operations continue as above outlined with the compensatory mechanism of Fig. 12 operating whernecessary to expand the hone in compensating for wear on the stones. The honing stones eventually become worn to such an extent that a part of the holder 11 for one or more of the hones engages with the workpiece, thereby establishing a circuit through the solenoid 23| to open the switch 204 and bring the machine iml mediately tol rest. The machine cannot then be started for successful operation until the worn stone or stones have been replaced.

Y From the foregoing it will be apparent that the present invention provides an arrangement by :s

which the rate of relative rotation of the hone and workpiece can be changed at a predetermined point during the honing operation where it is desirable to have varying rates of speed for obtaining the desired surface iinish. 'This change in the rate or speed is procured automatically Without interrupting the'honing operation. 'I'he invention also incorporates a mechanism by which to compensate for wear on the hones so that in combination with a work-loading mechanism the machine can be entirely automatic for the' successive honing of a plurality of work-pieces. Furthermore, the machine is arranged to provide for stopping further honing of workpieces when any of the honing' stones is worn to predetermined limit of size. Y

We claim,

1. In a honing machine, a hone having at least stopping the machine, said carrier forming a second contact in the circuit.

2. In a honing machine, a hone having a plurality of honing members thereon, a carrier plate for each honing member, a work-support for a workpiece, and means, including an electrical circuit having the workpiece as one contact thereof, said circuit being closed by engagement between the workpiece and any one of the carrier plates, for automatically stopping the machine, each of said carrier plates forming a contact in the circuit With any one of said carrier plates engageable with the workpiece for closing the circuit.

3. In a honing machine for the successive honing of a plurality of workpieces, a hone having a plurality of honing elements simultaneously engageable with a workpiece surface, a work-support, means for procuring honing operations on workpieces successively positioned in the worksupport, including means for terminating each honing operation and means for returning the hone and work-support to operative position after an unhoned workpiece has been placed in the work-support, and means for procuring a compensation for wear on the hone when suchy a compensation becomes necessary.

4. In a honing machine for the successive honing of a plurality of workpieces, a hone having a plurality of honing elements simultaneously' engageable with a workpiece surface, a work-support, means for procuring honing operations on Workpieces successively positioned in the worksupport, including means for terminating each honing operation and means for returning the hone and work-support to operative position after an unhoned workpiece has been placed in the work-support, and means for procuring a. compensation for wear on the hone independently of the individual honing operations and dependent upon the amount of wear on the hone.

5. In a honing machine for the successive hon- -ing of a plurality of Workpieces, a hone having a plurality of honing elements simultaneously engageable with a workpiece surface, a work-support, means for procuring honing operations on workpieces' successively positioned in the worksupport, including means for terminating each honing operation and means for returning the hone and work-support to operative position after an unhoned workpiece has been placed in the work-support, means for procuring a compensation for wear on the hone when such a compensation becomes necessary, and means for stopping the machine when the hone is worn away a predetermined amount.

6. In a honing machine, a hone having a plurality of honing elements simultaneously engage;- able with a workpiece surface, a work-support, means for procuring a movement of said worksupport relative to the hone for bringing a workpiece in the work-support into' honing position, timing means for procuring a change in honing operation, other timing means subsequently operative for bringing the honing operation to a close, and means responsive to said rst means for setting both timing means in operation.

7. In a honing machine, a hone having a plurality of honing elements simultaneously engage- `able with a workpiece surface, a work-support, means for procuring a relative rotation between these parts, means for procuring a movement of said work-support relative to the hone for bringing a workpiece in the support into honingposition, timing means for procuring a change in the rate of relative` rotation, other timing means for terminating the honing operation, and means responsive to said second means for setting both' timing means in operation.

8. In an abrading machine, an abrading member, a supporting member for the abrading member, a work-support for a workpiece, and means including a circuit having the workpiece as one contact thereof, said circuit being closed by engagement between the workpiece and the supporting member for automatically stopping the machine, said supporting member forming a contact in the circuit engageable with the workpiece.

HAROLD L. BLOOD.

.WILLIAM D. SCHMIDT. 

